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The most commonly used method of cooling is with vapor-compression cycles, because it is fairly

easy to construct a cooling device employing this method and the cost is low. In fact, conventional

refrigerators use this method of cooling to keep your leftovers and drinks chilled! Air conditioners

also employ a vapor-compression cycle to cool the ambient air temperature in a room.

A working fluid (often called the refrigerant) is pushed through the system andundergoes state changes (from liquid to gas and back).

Refrigeration is a process in which work is done to move heat from one location

to another.

Various fluids have been identified aspractical refrigerants. The most commoninclude ammonia, Freon (and otherchlorofluorocarbon refrigerants, aka CFCs),and HFC-134a (a non-toxic hydrofluorocarbon).

Power Consumption :Cold Storage : 2000-5000 KWDomestic Refrigerator : 100 – 250 KW

Domestic

Use

Commercial

Use

Transport

Purpose

The most important load for refrigerationcalculation is the Internal Load calculation

Flow of Refrigeration Load

Calculation

Site SurveyDivide the site planHeat Load CalculationSelection of Refrigeration equipment Pipe Design

We have to choose different types ofcooling for non vegetarian as well asvegetarian items.The calculations will be different for thosetwo as well.

Job: Design Ambient Temperature,

Storage Temperature and Humidity

Requirements, Dimensions, Insulation,

Type of Construction , Product.

The use of refrigerators in kitchens for storing

fruits and storing fish and meats safely for long

periods.

Liquefying gases like Oxygen, Nitrogen,

Propane Methane etc.

In oil refineries, chemical plants, and

petrochemical plants, refrigeration is used to

maintain certain processes at their needed low

temperatures.

Metal workers use refrigeration to temper

steel and cutlery.

In preservation of organic material.

Air Conditioning is the removal of heat from indoor air for

thermal comfort. Air Conditioner is the machine

which does this job.

Characteristics It is the mechanical way of regulating the temperature, Humidity control, Cleanliness, Air flow inside a room or a building.

Domestic

Use

Window A.C

Split A.C

Commercial

Use

Transport

Purpose

In Split AC Evaporator is indoors and Condenser is outdoors, connected by twopipes. A package system on the other hand has everything in one unit, usually onthe roof but sometimes on the ground and ductwork is run to the conditionedspace.

A drawback of split portable units is that a

surface exterior to the building, such as a

balcony must be provided for the external

compressor unit to be located.

Most split system air conditionersdo not introduce outside air forventilation, and only perform atemperature control function.

Windows Air Conditioners are one of the most widely used types of air conditionersbecause they are the simplest form of the air conditioning systems.

The whole assembly of the window air

conditioner can be divided into two

compartments:

The room side, which is also the cooling side

The outdoor side from where the heat absorbed

by the room air is liberated to the atmosphere.

The base of Window AirConditioner is assembled insidethe casing which is fitted into thewall or the window of the room inwhich the air conditioner is fitted.

Central Air Conditioners incorporate two different coils in order to cool complexes. This

type of cooling system is used to cool the entire home, versus a window air conditioner

that is used to cool a specific area or room of your home.

Chiller Air Handling Unit Ducts Grills Diffusers Insulation Centrifugal Pump

A Chiller is a machine that removes heat from a liquid via a vapour-compression

or absorption refrigeration cycle. This liquid can then be circulated through a heat

exchanger to cool air or equipment as required.

A typical chiller for air conditioning applicationsis rated between 15 to 1500 tons (180,000 to18,000,000 BTU/h or 53 to 5,300 kW) in coolingcapacity, and at least one company has a 2,700ton chiller for special uses.

Chilled water temperatures can rangefrom 35 to 45 degrees Fahrenheit (1.5to 7 degrees Celsius), depending uponapplication requirements.

An Air Handling Unit (often abbreviated to AHU), is a device used to condition andcirculate air as part of a heating, ventilating, and air-conditioning (HVAC) system.

An air handler is usually a large metal box

containing a blower, heating or cooling

elements, filter racks or chambers, sound

attenuators, and dampers. Air handlers

usually connect to a ductwork ventilation

system that distributes the conditioned air

through the building and returns it to the

AHU.

Small Air Handlers, for local use, are

called Terminal Units, and may only

include an air filter, coil, and blower; these

simple terminal units are called blower coils

or fan coil units.

A Diffuser is the mechanical device that is designed to control thecharacteristics of a fluid at the entrance to a thermodynamic open system.

The Diffusers which areconstructed in side-walls arecalled Grill Diffusers.

Diffusers are used to slow the fluid'svelocity and to enhance its mixing into thesurrounding fluid. In contrast, a nozzle isoften intended to increase the dischargevelocity and to direct the flow in oneparticular direction.

Here are some of the advantages of working

in an air conditioned environment:

Efficiency of the human beings increases

Better health

Less noise

Fresh air

The AC produces comfort conditions in which the human beings tend to feelhighly comfortable. In these conditions the working efficiency of the humanbeings becomes maximum, hence they are able to work with greater vigour.

Domestic application

Office buildings

Bank

Shopping complex

Hotels

Hospitals

Restaurants

Clubs

Resorts

Academic institutions

Transport systems

Defense

Airports

Aircrafts

Ships

Various industries including but not limited to

Steel plants Power plants Textile industries Pharmaceutical industries Food processing and preservation Petro-chemical plants IT industries Telecom industries Electronic and printing media Clean rooms

Variable refrigeration flow (VRF) is a multi and direct expansion type air conditioningsystem whereby one outdoor unit can be connected with multiples indoor units.

The term variable refrigerant flowrefers to the ability of the system tocontrol the amount of refrigerantflowing to the multiple evaporators(indoor units), enabling the use ofmany evaporators of differingcapacities and configurationsconnected to a single condensingunit. The arrangement provides anindividualized comfort control, andsimultaneous heating and cooling indifferent zones.Currently widely applied in largebuildings especially in Japan andEurope, these systems are juststarting to be introduced in the U.S.The VRF technology/system wasdeveloped and designed by DaikinIndustries, Japan who named andprotected the term variablerefrigerant volume (VRV) system soother manufacturers use the termVRF "variable refrigerant flow".

Comfort

Design Flexibility

Flexible Installation Energy Efficiency

Reduced Noise Levels

With a higher efficiency and increased controllability, the VRF systemcan help achieve a sustainable design. Unfortunately, the design of VRFsystems is more complicated and requires additional work compared todesigning a conventional direct expansion (DX) system.

We have used Carrier E20 form, which is based on Instantaneous Peak Load Method

For a thorough calculation of the zones and whole-building loads, one of the following three

methods should be employed

Transfer Function Method (TFM)

Cooling Load Temperature Differential/Cooling Load Factors (CLTD/CLF)

Total Equivalent Temperature Differential/Time-Averaging (TETD/TA)

According to Carrier Handbook for HVACR Engineers, for the Coordinates of the City of Kolkata, the highest load of the year is obtained on 21st of May at 16.00 hrs.

Heat Load measures the

capacity of the space

heating system required to

maintain comfortable

indoor temperatures at any

one time, specified in Watts

per square metre of treated

floor area.

The heat load is determined by the

sub sequent steps:

Calculating the areas separately

Determining the number of

peoples and appliances

Putting values in the sheet.

Psychometrics or psychometric or hygrometryare terms used to describe the field ofengineering concerned with the determinationof physical and thermodynamic properties ofgas-vapor mixtures

Psychometric properties

Dry-bulb temperature (DBT)Wet-bulb temperatureRelative humidityDew point temperatureSpecific enthalpySpecific volume

We have selected duct able split AC as it is a commercial application.

AS OUR HEAT LOAD IS 41 TR, WE HAVE SELECTED 4X11TR UNITS. i.e.

(4X11) = 44TR (10% extra as future provision)

We have selected scroll

compressor based model for

better energy efficiency than

reciprocating compressors

from popular branded AC

Companies like Blue Star

Ltd, Voltas Ltd, Carrier AC

& RF Ltd.

We have seen that the

commercially available models

range from 5.5TR, 8.5TR,

11TR, 17TR*.

Ducts are used in heating, ventilation, and air conditioning (HVAC) to deliver andremove air.

Ducts can be made out of the following materials: Galvanized mild steel,Polyurethane and Phenolic insulation panels (pre-insulated air ducts)

In industrial applications, commercially, duct designs are done through duct sizing

table in Carrier Handbook, Mechanical Ductulator, McQuay Duct Sizer Software

etc. Here, in our project, we have used McQuay Duct Sizer.

The chief requirements of an air

conditioning duct system are:

It should convey specified rates of air flow to

prescribed locations.

It should be economical in combined initial

cost, fan operating cost and cost of building

space.

It should not transmit or generate objectionable

noise.

The Duct Design is done in the sub sequent steps

From Cooling Load & Psychometric Calculations, the required supply air flow rate is determined.

From building layout and location of supply fan (IDU), the length of each duct run is determined.

Suitable dimensions of the duct are selected after each air discharge.

The duct design methods

Velocity Reduction Method

Equal Friction Method

Static Regain Method

Were we to break down the process into its core components, this is what a contractor would do when sizing your duct work:

Determine CFM for EachFriction Loss RateDuct Sizing

The main advantages of using glass wool are :

Excellent thermal insulation,

Unique lightness,

Thin solution,

Optimal acoustic performance,

Active environmental protection,

Cost effective solution.

Insulation is essential in central AC plants as there are really long pipes and ducts

carrying cold water and air respectively. Without proper insulation the cold water andair will gain from the surrounding.

Duct insulation is available in 1 and 2-inch thicknesses.

Outdoor Duct Insulation is comprised of two aluminiumfoil facings, separated by a dual layer of polyethylenebubble pack, glass wool, cotton etc